Ancient Life Remains Found in Mysterious Rocks
AFP
Where Life Began?
Jan. 29, 2008 -- Claims that microbial life began on Earth billions of years
ago have been given support from a French team which drilled into mysterious
layers of spongy rock in Western Australia.
Researchers from the Institute for Global Physics in Paris used a technique
called nanospectroscopy to pore over cores drilled from an enigmatic rock
formation in the Pilbara region.
Palaeo-geologists from around the world have been lured to Pilbara, famous for
rock layers in the shape of cones, waves and "egg carton" domes.
One school of thought holds that these layers comprise the fossilized remains
of bacteria, called stromatolites, that seethed in shallow seas or lake water,
which washed over the area when the Earth was young.
Others, though, dispute a microbial origin, and say the shapes were the result
of chemical weathering, a reaction between the rock and sea water, or
hydrothermal vents.
The French investigators, led by Kevin Lepot, drilled a deep core of rock from
the Pilbara's Tubiana formation at Meentheena and took images of the sample to
a resolution of 10 nanometers, or 10 billionths of a meter.
They found minute crystals of aragonite, a calcite residue from dead
micro-organisms.
Previous research have dated the Tubiana rocks to 2.72 billion years.
In 2006, Australian and Canadian researchers led by Abigail Allwood of Sydney's
Macquarie University dated microfossils in rocks from Pilbara's Strelley Pool
Chert formation at more than 3.4 billion years old, the earliest evidence so
far of life on Earth.
Dating of early life on Earth could help determine whether life exists, or has
existed, on Mars, the best bet for microbial life forms in other planets of the
solar system.
Mars once had an atmosphere and was awash with water -- two ingredients that,
with warmth, comprise the essentials for bacterial life.
The new study appears in the February issue of the journal Nature Geoscience,
published by Britain's Nature group.
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Related Links:
Larry O'Hanlon's blog: Earth Impacts
The Pilbara Region
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